<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
</head>
<body>

<script>
    
/*var foo = '' ;
var bar = 'aaa';
//foo = foo && bar;
console.log( !foo +'   +   '+ !bar );
//console.log( (foo = foo || bar) + '或或'  );


console.log( (foo = foo && bar) + '与与' );*/


/*if ( !foo == false ) {
    foo = bar ;
}
console.log( foo );*/

/*if( !foo ) {
    foo = bar;
}

console.log( '==============================================================' );

console.log( foo + '判断' );*/



/*var foo;
var number = 1;
var string = "string";
var obj = {};
var arr = [];
 

 
console.log(typeof(!!foo));  // boolean
console.log( !!foo );
console.log(typeof(!!number));　　//boolean
console.log(typeof(!!string));　　//boolean
console.log(typeof(!!obj));　　//boolean
console.log(typeof(!!arr));　　//boolean*/

function Fn(){
  return Fn;
};
fn =new Fn();
console.log(fn instanceof Fn);

//我修改了


</script>



</body>
</html>